First of all they are clouds made of ice crystals that are extremely high up (75-85 km according to wikipedia). They can only be seen around twilight since they are then illuminated from underneath by the Sun that has already set. They are mostly seen from highish latitudes (50-70 degrees – I am at around sixty degrees). They are fairly uncommon.

What does this mean for regular folks? Well not much… Mostly it means that today is the longest day and at midday the Sun is as high in the sky as it gets during the year. In many countries this day marks the start of summer. Happy days…

Astronomically it is the day when the Earth’s axis tilt is most inclined towards the Sun. In the northern hemisphere this happens around the 20th or 21st of June and in the southern hemisphere around the 21st or 22nd of December.

In the image above (taken from APOD) the Sun is photographed at the same time of day throughout the year. The path it traces is called an analemma. Summer Solstice occurs on the day the Sun is at its highest. The figure of eight is caused because the Earth’s orbit is slightly elliptical and the Earth moves faster in its orbit when closer to the Sun. This means that in some parts of the year the Sun is further along in its path over the sky and at others it is behind.

The 24th June I took a day off to spend some time with my two grown up daughters. We try to do this every now and again and spend the day experiencing something new. This time we agreed to visit the Darwin exhibition at the Zoological Museum in Oslo. The main object of the trip was to have a look at the fossil Ida (be patient – we will get to her) which is a part of the exhibition. The museum is beautifully situated in Tøyen park.

The gardens there were lovely:

The exhibition was very interesting and well worth visiting though difficult to photograph because of the low light levels. It was very encouraging that many children were visiting the exhibition.

The exhibitions sub-title (the title of this post) irritated me. That was perhaps the point…

<Start rant…
Why do we need to forgive Darwin? Science deals with physical evidence not beliefs. Darwin gave the world the best explanation of the physical evidence as to how life came to be as it is. His theory has, with improvements as our knowledge improves, stood the test of time for 150 years and is extremely well supported by the evidence. Evolution is as close to being a fact as any scientific theory can be. Should we forgive Copernicus for his formulation the Heliocentric Theory? Or Newton for his formulation the Theory of Gravity? That is silly. You don’t forgive theories you disprove them – if you can. So far nobody has.…End rant>

The exhibition teaches us that Darwin’s concept is based on four premises and one conclusion:

Premise number 1: Inheritance

We inherit traits from our parents. Eye-colour, muscular strength, singing voice, the shape of our ears and the kinds of food we prefer – all is to some extent inheritable. Darwin grew up in the countryside and was well versed in how farmers used animal traits in animal breeding.

Premise number 2: Variation

No two people are exactly the same. Even identical twins are not quite identical. the same goes for all organisms. This was already known in Darwin’s time, but the reason for these differences was a mystery. Genes and mutations were not discovered until the 20th century.

Premise number 3: The struggle for existence

Darwin was fascinated by the economist Thomas Malthus, who wrote that populations will grow faster than the necessary resources. This holds true for all animal species: Many more are born than grow up. A female cod will spawn millions of eggs during her life, yet on average only two will reach maturity.

Premise number 4: Natural selection

Survival is not a random process! Some individuals have traits that help them in the struggle for life. It is these individuals who are most likely to reach maturity and breed, transferring their traits to the next generation. Their traits will then become more common with each generation, while the traits belonging to those who did not breed will fade away.

The conclusion: Species change over time

In Darwin’s time, it was commonly believed that each species had ‘always been like that’. The conclusion of Darwin’s theory was that species are not that constant. Even small changes in the environment will make species change and new species appear. Darwin argued that all organisms share a common ancestor.

And so to our great aunt Ida (Darwinius masillae).

This is what experts think Ida looked like:

Here are images of the fossil taken through the glass case – hence the reflections.

On May 25, 1961, President John F. Kennedy announced before a special joint session of Congress the dramatic and ambitious goal of sending an American safely to the Moon before the end of the decade. A number of political factors affected Kennedy’s decision and the timing of it. In general, Kennedy felt great pressure to have the United States “catch up to and overtake” the Soviet Union in the “space race.” Four years after the Sputnik shock of 1957, the cosmonaut Yuri Gagarin had become the first human in space on April 12, 1961, greatly embarrassing the U.S. While Alan Shepard became the first American in space on May 5, he only flew on a short suborbital flight instead of orbiting the Earth, as Gagarin had done. In addition, the Bay of Pigs fiasco in mid-April put unquantifiable pressure on Kennedy. He wanted to announce a program that the U.S. had a strong chance at achieving before the Soviet Union. After consulting with Vice President Johnson, NASA Administrator James Webb, and other officials, he concluded that landing an American on the Moon would be a very challenging technological feat, but an area of space exploration in which the U.S. actually had a potential lead. Thus the cold war is the primary contextual lens through which many historians now view Kennedy’s speech.

The above clip is from NASA’s page on President Kennedy’s announcement of the decision to go to the Moon.

Here is an audio recording of the speach I found on YouTube.

Twelve people have walked on the surface of the Moon.

Apollo 11

Neil Armstrong – Commander

Edwin E. Aldrin, Jr. – Lunar Module Pilot

Apollo 12

Charles Conrad, Jr – commander

Alan L. Bean – lunar module pilot

Apollo 14

Alan B. Shepard, Jr – Commander

Edgar D. Mitchell – Lunar Module Pilot

Apollo 15

David R. Scott – Commander

James B. Irwin – Lunar Module Pilot

Apollo 16

John W. Young – Commander

Charles M. Duke Jr. – Lunar Module Pilot

Apollo 17

Eugene A. Cernan – Commander

Harrison H. Schmitt – Lunar Module Pilot

Apollo 17 left the surface of the Moon on 14th December 1972. We have not been back since then.